V2Rocket

What precisely differentiates the DME out of, say a 1986 951 and an early 944? Is there some other input signal relating to the turbo at all, or is it just remapped for different fuel setups?

MM951

if you look at a dme pinout fora 951 you will see there are pins that would serve no function on an n/a

early 944 dme is much different then a 951 dme

for example early dme relies on a 0-12v signal from the afm, the late cars use a 0-5V signal (like most modern cars) , irrc even if it would start when the early afm is not even 1/2 maxed outthe DME out be seeing 5v and would think the car is at high rpms/load

V2Rocket

for that a 5v AFM could be used, right?

what do the extra pins do?

amet

amongst other things the 944 N/A,early and late, use 130 Tooth Starter Gear while turbos use 132 Tooth Starter Gear.

signal from the speed/ref sensors will be different unless you change the starter gear to match the DME.
+ AFM part numbers for 944 N/a late (0-5 v) and 944 turbo are different so that leads me to believe that the signal would be somehow different.

FRporscheman

turbos have knock sensors and early NAs don't (right?) and turbos have that extra turbo cooling water pump